Use of spit (smokeless) tobacco (ST) is increasing in prevalence among young American males, is especially prevalent among those residing in rural areas, and puts them at risk of oral cancer, and periodontal tissue destruction. This proposal has the following specific aims: (1) to determine the efficacy of a school-based nurse-directed, per- and dentist-assisted ST intervention program among male students in 28 high schools in rural areas of California and (2) to determine predictors of successful ST cessation among male students in rural high schools. The intervention is based on Cognitive Social Learning Theory and Diffusion of Innovation Theory and applies a public health perspective by approaching ST users in their environment and Innovation Theory and applies a public health perspective by approaching ST users in their environment and attempting to change social norms to effect behavioral change. Twenty-eight rural high schools in California will be stratified on baseline prevalence of male ST use and size of enrollment and randomly assigned within strata to either the intervention or the control group. The intervention will consists of a school advisory board; peer-led educational sessions; an oral exam and advice to quit or to stay tobacco-free by a school nurse who points out any ST-associated lesions to users by their own mouths or in photographs, provides brief cessation counseling, and facilitates three group follow-up relapse prevention sessions, conducts 1-week follow-up examines of students with ST-related oral lesions, and schedules students with persistent lesions for evaluation by a dentist; and, two follow-up telephone cells by a peer to prevent relapse. Biochemically validated self-reported quit rates and self reported initiation rates at the end of the intervention and 1 year later will be compared between groups. Baseline and follow-up questionnaire assessments of ST use will be analyzed to identify individual characteristics that are associated with quitting ST use. Results will contribute to the body of knowledge related to tobacco prevention and cessation and thereby to the primary and secondary prevention of oral cancer and other negative oral health effects associated with tobacco use.